Sundaramoorthy Gopi

Retinal pigment epithelium (RPE) degeneration remains a formidable challenge in dry age-related macular degeneration (AMD) research, primarily due to the toxic interplay between iron overload and ferroptosis. We investigated whether EPO-R76E, a non-erythropoietic modified variant of erythropoietin, could effectively interrupt this destructive cycle. Using ARPE-19 cells challenged with ferric ammonium citrate (FAC) to model iron-induced toxicity, we show that EPO-R76E confers protection against ferroptosis. Our results demonstrate that this variant significantly reduces the intracellular labile iron pool, directly quenching the lipid peroxidation that drives ferroptotic cell death. This resilience is fueled by a robust upregulation of Glutathione Peroxidase 4 (GPX4) and the broad transcriptional activation of the NRF2 (Nuclear factor erythroid 2-related factor 2) NRF2 antioxidant axis. Furthermore, we found that EPO-R76E enhances autophagic flux, ensuring that cells maintain essential proteostasis and “housekeeping” functions even under metabolic crisis. By integrating iron sequestration with reinforced antioxidant signaling and cellular clearing mechanisms, EPO-R76E stands out as a potent candidate for preserving RPE health. These findings uncover a novel molecular framework for protecting the retina against iron-mediated injury, positioning EPO-R76E as a versatile and targeted gene-based therapeutic for addressing the fundamental causes of retinal degeneration.

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss, primarily driven by oxidative stress–induced degeneration of retinal pigment epithelium (RPE). Erythropoietin (EPO), a hematopoietic cytokine with neuroprotective properties, has been shown to reduce apoptosis and retinal degeneration. In this study, we examined the cytoprotective role of a non-erythropoietic EPO variant, EPO-R76E, in suppressing oxidative stress and mitochondrial dysfunction related to oxidative stress in RPE cells. Stable ARPE-19 cell lines expressing EPO-R76E were generated via lentiviral transduction and exposed to paraquat to induce oxidative stress. Oxidative stress was induced using paraquat. EPO-R76E expression conferred increased cell viability and resistance to mitochondrial damage, as assessed by cytotoxicity assays. Western blot analysis revealed reduced expression of ferritin and p62/SQSTM1, diminished activation of p-AMPK and NRF2, and restoration of GPX4 levels, indicating enhanced antioxidant defenses. Moreover, intracellular iron accumulation and reactive oxygen species were significantly reduced in EPO-R76E-expressing cells exposed to paraquat. These findings suggest that EPO-R76E promotes mitochondrial homeostasis and modulates oxidative stress pathways. Our study positions EPO-R76E as a promising therapeutic candidate for halting RPE degeneration in AMD.

Aim To identify the genetic etiology of neonatal diabetes in an infant and to elucidate the molecular mechanism of the identified mutation underlying the pathogenesis. Methods Genetic analysis was carried out by sequencing of known etiological genes associated with NDM. Molecular characterization was performed by constructing a identified mutation in NKX2-2 gene and functional aspects was tested using transactivation, protein expression, DNA binding, nuclear localization assays. Structural analysis was performed by modeling the NKX2-2 protein structure. Results A novel homozygous frameshift mutation c.772delC, p.Q258SFs*59 in the NKX2-2 gene was identified in a patient with neonatal diabetes. Functional studies revealed that this mutation resulted in an elongated protein sequence, affecting DNA binding activity and transcriptional function. Structural analysis suggested alterations in the protein’s tertiary structure, likely contributing to its dysfunction. Conclusion This study presents the first report of a stop-loss mutation in the NKX2-2 gene associated with NDM. Our findings emphasize the importance of functional and structural characterization to understand the biological consequences of such mutations. This comprehensive analysis provides insights into the molecular mechanisms underlying NDM and its clinical phenotype, which may aid in better diagnosis and management of patients with similar variants in the future.